Middle East Respiratory Syndrome (MERS) is viral respiratory illness first reported in Saudi Arabia in 2012. It is caused by a coronavirus called MERS-CoV. Most people who have been confirmed to have MERS-CoV infection developed severe acute respiratory illness. They had fever, cough, and shortness of breath. About half of these people died.

So far, all the cases have been linked to four countries in or near the Arabian Peninsula. No cases have been identified in the U.S. This virus has spread from ill people to others through close contact. However, the virus has not shown to spread in a sustained way in communities. The situation is still evolving.

CDC is working with partners to better understand the risks of this virus, including the source, how it spreads, and how infections might be prevented. CDC has provided information for travelers and is working with health departments, hospitals, and other partners to prepare for possible cases in the United States.